1. Field of the Invention
The invention relates to tank type vacuum cleaners and more particularly to the type of vacuum cleaner that is especially adapted to use in the home, in the workshop, and in industry as a wet or dry type vacuum and the primary object of the present invention is to provide an improved device of this character.
2. Description of Prior Art
The wet or dry shop vacuums presently in the marketplace characteristically consist of on open top collection tank mounted on wheels or casters and a cover or lid in which an electric motor and blower unit are mounted. The blower unit creates a suction within the tank and debris and liquid are drawn into the tank through a vacuum hose which is connected to an inlet located in the cover of the tank or to an inlet located high on the side of the tank itself. The air being drawn from the inside of the tank and through the blower is filtered to prevent dust and debris from reaching the motor and blower unit and to prevent dust and debris-laden exhaust from being expelled into the environment in which the vacuum is being operated. While filter methods vary, the most usual is a cylindrical filter of paper, cloth, or other porous material suspended from the cover of the tank and incorporating a check ball or float arrangement which cuts off suction to the blower unit should the liquid level in the tank rise to a level at which it threatens to enter the motor and blower unit itself, a condition which could occur in vacuums which feature an inlet located in the cover and higher than the blower intake, but not likely to occur in units which feature a vacuum inlet in the side of the tank and below the level of the blower intake.
The advantages of the above described arrangements are apparent to anyone practiced in the art: (1) the blower and electric motor unit is relatively isolated from debris and especially from liquids coming into and being stored in the tank, (2) the arrangement readily lends itself to a filter and filter housing located below the motor and blower unit, attached to the cover, and containing a simple ball or float check valve, (3) the location of the vacuum inlet which connects to the vacuum hose in the cover of the assembly or at a point high up along the side of the tank makes it possible for a large amount of debris and liquid to accumulate in the tank before such accumulation reaches a level which would close off the vacuum inlet and (4) the location of the heavy operating machinery of the vacuum in and attached to the cover of the assembly makes for convenience and ease of emptying the tank inasmuch as the weight of the operating machinery is removed when the cover is removed.
The disadvantages of the above described arrangements are readily apparent to anyone who has ever actually used the wet or dry shop vacuums which are currently in the marketplace and fit the above description: (1) the location of the electric motor and blower unit at the top of the assembly creates a high center of gravity which results in extreme vertical instability for the entire assembly and (2) the location of the vacuum hose inlet in the cover at the top of the assembly or in the side of the tank a short distance down from the top of the tank causes the operator to exert substantial leverage on the inherently unstable assembly when the operator attempts to drag the vacuum forward using the vacuum hose as the tow line. When the casters or wheels on which the assembly is mounted encounter any debris or obstruction, or even such resistance as is offered by a thick pile carpet, and the operator attempts to pull the unit forward using the vacuum hose as a tow line, the combination of high center of gravity and substantial leverage resulting from the high connection point for the vacuum hose conspire to cause the vacuum cleaner assembly to capsize.
Some of the prior art attempts to deal with the problem of vertical instability by locating the motor and blower unit at the bottom of the vacuum cleaner assembly, but the prior art solutions are accompanied by disadvantages which are unacceptable and unsuited to vacuum cleaners having a wet function. U.S. Pat. No. 3,286,446 issued to Happe et al on Nov. 20, 1966 is an example of such art. With the motor and blower unit located at the bottom of the tank or canister, the Happe vacuum collects dust and debris in a dust or filter bag which is suspended above the motor/blower unit. The disadvantages of such an arrangement are several including (1) dust or filter bag arrangements are not suited to a wet vacuum use because a filter bag will not contain moisture and liquids will descend onto the electric motor and blower unit, (2) the filter area of a dust or filter bag rapidly decreases as debris accumulates in the bag and (3) dust bags are essentially messy to use and messy to empty and a dust bag of sufficient size to offer the accumulation area associated with shop vacuums would be especially messy to use and to empty. The Osborn patent, U.S. Pat. No. 2,771,151 issued Nov. 20, 1956 locates the motor and blower unit at the bottom of the assembly, in this case a canister type vacuum, and offers some solution to the problem of decreasing filter area which is caused by the accumulation of debris, but the unit is unsuited to wet/dry operation for the reasons cited above.
The extreme vertical instability of wet or dry shop vacuums now in the marketplace results from a concurrence of two conditions, (1) the high center of gravity of the vacuum assembly which is produced by locating the heavy operating machinery high in the vacuum cleaner assembly and, (2) the substantial leverage produced when the wheels or casters at the bottom of the assembly encounter obstruction or resistance and the operator attempts to move the assembly by pulling on the vacuum hose, the vacuum hose being connected at the top, or near the top, of the assembly.
The present invention is specifically directed to overcoming the first of these problems in a novel and simple manner. The second of these problems is solved in a novel and simple manner by the invention disclosed in co-pending Application entitled "Improved Vacuum Cleaner Assembly with Low Vacuum Inlet".
3. Summary of the Invention--Objects and Advantages
The principal object of the present invention is to provide a tank type shop vacuum suited to wet or dry operation in which the heavy operating machinery, specifically the electric motor and connected blower unit, are located low in the assembly so as to produce a low center of gravity and substantially enhanced vertical stability for the entire assembly.
Another object of the present invention is to house the electric motor and connected blower unit in such a manner as to protect the electric motor from liquids stored in the accumulation area of the tank and from the sometimes moisture-laden air passing through the blower unit.
Another object of the invention is to cool the electric motor with air drawn from outside the assembly as opposed to cooling the motor with the sometimes moist air being drawn from the tank and passing through the blower unit;
Another object of the invention is to evacuate air from the tank through a conventional filter, suspended in the conventional manner at the top of the tank interior and utilizing a conventional ball-type check valve and to confine and direct such air by a conductor means from the filter unit at the top of the tank to the blower at the bottom of the tank, with the conductor both air tight and liquid tight throughout its length and at all connections.
Another object of the present invention is to accomplish the above described objects in a manner that is unique, simple, and which lends itself to relative ease of assembly and to production costs which are competitive with other wet or dry shop vacuums now in the marketplace. Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description